PowerPoint to accompany
Technology of Machine Tools
6th Edition
Krar • Gill • Smid
Milling Machines
Section 12
Copyright © The McGraw-Hill Companies, Inc.
Permission required for reproduction or display.
59-2
Milling Machines
• Used to produce one or more machined
surfaces accurately on workpiece
– One or more rotary milling cutters
• Workpiece held on work table or holding
device and brought into contact with cutter
• Vertical milling machine most common
• Horizontal milling machine handles
operations normally performed by other tools
PowerPoint to accompany
Technology of Machine Tools
6th Edition
Krar • Gill • Smid
The Vertical Milling
Machine
Unit 59
Copyright © The McGraw-Hill Companies, Inc.
Permission required for reproduction or display.
59-4
Objectives
• List four main uses of a vertical milling
machine
• Describe how angular surfaces can be
machined
• List three types of vertical milling
machines
• State the purposes of the main parts of a
knee and column machine
59-5
Vertical Milling Machine
• Developed in 1860's
• Combines vertical spindle of drill press with
longitudinal and traverse movements of
milling machine
• Milling process may be vertical, horizontal,
angular, or helical
• Can be used for milling, drilling, boring, and
reaming
• Can machine in one, two, or three planes
– X, Y, Z
59-6
Vertical Milling Machines
• Equipped with variable speed spindle drives
– Permit wide range of speeds
• Spindle head housing swiveled as much as
90 degrees right and left, as well as limited
backward and forward for angular operations
• Longitudinal and crossfeed movements of
table operated by hand or automatic feeds
59-7
Variety of Operations
•
•
•
•
•
Face milling
• Gear cutting
End milling
• Drilling
Keyway cutting
• Boring
Dovetail cutting
• Jig boring
T-slot and circular
Many facing operations
slot cutting
done with fly cutter
(cost reduction).
59-8
Types of Vertical Milling
Machines
• Ram-type
–
–
–
–
Most common because of simplicity and setup
All features of plain horizontal milling machine
Cutter spindle mounted in vertical position
Spindle head may be swiveled allowing
machining of angular surfaces
• 2-axis control
– Step between standard milling machine and
CNC machining center (PC control)
59-9
Heavy-Duty Vertical Milling
Machine
• Used for machining operations that require
larger cutters and good rigidity
• Adapted to operations with end mills and
face mills
– Profiling interior and exterior surfaces
– Milling dies and metal molds
– Locating and boring holes in jigs and fixtures
59-10
Ram-Type
Vertical Milling
Machine
59-11
Parts of Ram-Type Vertical Mill
• Base made of ribbed cast iron
– May contain coolant reservoir
• Column often cast with base
– Machined face provides ways for vertical
movement of knee
– Upper part machines to receive turret where
overarm mounted
59-12
Parts of Ram-Type Vertical Mill
• Overarm round and may be adjusted toward
or away from column
• Head attached to end of ram
– Made to swivel head in one plane
– Universal-type machines allow swivel in 2 planes
• Motor mounted on top of head
– provides drive to spindle through V-belts
59-13
Parts of Ram-Type Vertical Mill
• Spindle speed changed by variable-speed
pulley/crank or by belt changes and
reduction gear
• Knee moves up and down on face of column
– Supports saddle and table
– Does not contain gears for automatic feed
• Automatic feed is external device and controls
longitudinal and crossfeeds of table